Center for Marine Biodiversity and Conservation

We analyzed the spatial distribution, concentration, and characteristics of plastic micro-debris in neuston samples from the CalCOFI region off the Southern California Coast from winter cruises in 1984, 1994, and 2007. By sorting archived CalCOFI zooplankton samples, we were able to separate micro-debris particles and characterize particle size, circularity, and surface area using digital image analysis by ZooScan. Our results suggest that plastic micro-debris is widespread in the California Current System off the Southern California Coast. Fifty-six to 85% of the CalCOFI stations had detectable plastic micro-debris present, with an increasing trend in occurrence over time. Although the average concentration, length, and mass of the particles was not significantly different over the three decades, not only is plastic micro-debris widely distributed, it has been present in the Northeast Pacific ocean water column for at least 25 years.